Inhaler 624

ABSTRACT

The present invention relates to an Breath actuated inhaler (BAI) actuator, comprising: a loading element capable of being loaded with an actuation force, a breath actuated trigger mechanism arranged to counteract the actuation force of the loading element, and to fire the actuator by releasing the actuation force of the loading element in response to an inhalation breath, and actuation locking means moveable between a locked position wherein it relieves the actuation force from the trigger mechanism setting the trigger mechanism in a neutral position, and an armed position wherein the trigger mechanism is set in an armed position.

RELATED APPLICATIONS

Under 35 U.S.C. §119(e)(1), this application claims the benefit of priorU.S. provisional application 60/883,076, filed Jan. 2, 2007.

TECHNICAL FIELD

The present invention relates to an inhaler for delivery of a medicamentby inhalation and in particular to the actuation mechanism used in theinhaler to actuate a canister to dispense a dose of medicament.

BACKGROUND OF THE INVENTION

Inhalers are commonly used for delivery of a wide range of medicaments.The inhaler holds a canister of medicament, the canister being actuatede.g. by compression to deliver a dose of medicament through a mouthpieceto a user. The inhaler may be provided with an actuation mechanism toactuate the canister automatically and thus dispense a dose ofmedicament. Some known actuation mechanisms are breath-actuated, so thatthey operate in response to inhalation by a user. This ensures that adose of medicament dispensed on actuation of the canister is suppliedwhilst the user is inhaling. This is particularly useful for those userswho may find it difficult to co-ordinate the dispensing of a dose ofmedicament, by for example, the actuation of a button, with inhaling thedose.

A known breath-actuated inhaler has an actuation mechanism operable bycompression of a canister of medicament to deliver a dose of medicamentin response to inhalation by a user. The actuation mechanism comprises aloading mechanism to bias compression of the canister. A triggeringmechanism holds the loading mechanism against compression of thecanister. When delivery of a dose of medicament is required, thetriggering mechanism releases to allow compression of the canister inresponse to inhalation by the user. An actuating means is connected to acover for the mouthpiece and is responsive to the closing movement ofthe cover for re-setting the actuation mechanism. Such an arrangementresults in the components of the trigger mechanism not being loaded whenthe inhaler is not in use. When the cover is closed, critical force isredirected from the triggering mechanism during storage (cap closed).Over time, loading of critical components can quicken the onset ofmaterial creep, resulting in mechanical failure of the inhaler and itssubsequent inability to deliver a dose of medicament after a number ofuses. This situation can be extremely dangerous for the user in anemergency when it is vital that the inhaler deliver a dose whenrequired.

SUMMARY OF THE INVENTION

It is, for reasons mentioned above, an object of the present inventionto provide an inhaler incorporating such an actuation mechanism toalleviate the problems described above.

Accordingly, there is provided a breath actuated inhaler (BAI) actuator,comprising:

a loading element capable of being loaded with an actuation force,a breath actuated trigger mechanism arranged to counteract the actuationforce of the loading element, and to fire the actuator by releasing theactuation force of the loading element in response to an inhalationbreath, andactuation locking means moveable between a locked position wherein itrelieves the actuation force from the trigger mechanism setting thetrigger mechanism in a neutral position, and an armed position whereinthe trigger mechanism is set in an armed position.

In this way, components of the trigger mechanism and finely tolerancedparts are not loaded at any time, either when the inhaler is reset ordischarged, except for when the actuator is armed and ready to deliver adose of medicament. By avoiding heavy loading of the trigger mechanism,the onset of material creep is significantly reduced, resulting in aninhaler that may be re-used more safely.

Preferably, the loading means further loads the canister with anactuation force for compression of the canister from a rest position tothe charging position. Movement of the activating means to the firstposition applies a force directly to the loading means to compress thecanister from the rest position to the charging position. By providingsuch an arrangement, the canister may be pre-compressed thus reducingthe mechanical shock prior to the compressing of the canister to delivera dose of medicament.

Preferably, movement of the actuating means between the first positionand the second position applies a force directly to the loading means ina direction substantially along the cylindrical axis of the canister.

Preferably, the loading means comprises a resilient loading elementarranged to be loaded with an actuation force, the resilient loadingelement being arranged when loaded to bias compression of the canister.Typically, the resilient loading element is in a loaded state in whichthe resilient loading element stores the actuation force.

The resilient loading element may be a coiled plastic or metal spring.However, alternative arrangements may be envisaged that are able tostore and release an actuation force, such as compressed air, a tensionspring, an electric motor etc.

Preferably, the trigger mechanism comprises a lever member and a leverlock member, the lever lock member having a locked position and being soarranged as to hold the lever member in a locked position to holdloading means against compression of the canister.

Preferably, the latch means comprises a trigger element and a droplinkelement, movement of the trigger element to its latch release positioncauses movement of the droplink element to its latch release position,thereby moving the lever lock from its lock position to a releaseposition, causing the lever to move from its locked position to arelease position thereby allowing compression of the canister to releasea dose of medicament. The droplink element may further comprise a re-setposition. This enables the droplink element to readily take up its latchposition.

Alternatively, the trigger element is arranged to be moved to theunlatched position by the application of a manual action by the userinto the latch release position described above. For example, a firingbutton may be provided for manual depression by the user which serves tocontact the trigger element to move the trigger element.

Preferably, the actuation mechanism is breath-actuated, the triggerelement being arranged to be moved to the latch release position byinhalation at the mouthpiece to cause operation of the actuationmechanism. The trigger element may be an inhalation responsive triggervane.

Preferably, the actuating means is mounted for pivotal movement to applya force directly to a yoke. The actuating means may be a protectivecover or cap (see comment on page 2).

BRIEF DESCRIPTION OF THE DRAWINGS

To allow a better understanding, embodiments of the present inventionwill now be described, by way of non-limitative examples only, withreference to the accompanying drawings, in which:

FIG. 1 is a front perspective view of one embodiment of an inhaler withthe actuating means in the open position;

FIG. 1 a is a rear perspective view of the inhaler of FIG. 1 with theactuating means in the open position;

FIG. 2 is a side view of the inhaler of FIG. 1 with the actuating meansin the open position;

FIG. 3 is a side view of the canister module removed from the inhaler ofFIG. 1;

FIG. 3 a is a front perspective view of the canister module removed fromthe inhaler of FIG. 1;

FIG. 4 is a schematic side view of one embodiment of an actuationmechanism in the neutral or “rest” position;

FIG. 4 a is a corresponding perspective view of the actuation mechanismof FIG. 4 in the neutral or “rest” position;

FIG. 5 is a schematic side view of the actuation mechanism of FIG. 4 inthe armed or “charging” position;

FIG. 5 a is a corresponding perspective view of the actuation mechanismof FIG. 4 in the armed or “charging” position;

FIG. 6 is a schematic side view of the actuation mechanism of FIG. 4 inthe triggered “medicament discharging” position;

FIG. 6 a is a corresponding perspective view of the actuation mechanismof FIG. 4 in is the triggered “medicament discharging” position;

FIG. 7 is an exploded view of the components of the inhaler of FIG. 1with an actuation mechanism of FIG. 4.

FIGS. 8 a to 8 f show schematic side views of a number of states ofoperation for an embodiment of a breath actuated inhaler (BAI) actuator,with a schematic actuation mechanism.

FIG. 9 shows an alternative actuation mode for the BAI actuatoraccording to FIGS. 8 a to 8 f.

FIGS. 10 a and 10 b show perspective views of one embodiment of arelease member and a trigger element of a trigger mechanism.

FIGS. 11 a and 11 b show perspective views of another embodiment of arelease member and a trigger element of a trigger mechanism.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIGS. 1, 1 a, 2 and 7, one embodiment of a breathactuated inhaler (BAI) actuator 100, with respect to this embodimentreferred to as an inhaler 100, has a housing 10 comprising side walls12, a rear wall 14 and a top wall 16. The rear wall 14 forms a curvedsurface to facilitate comfortable receipt of the inhaler 100 in the palmof the user's hand. The walls 12, 14, 16 of the housing 10 define aspace for accommodating a canister 20 of medicament in a chassis 40, andan actuation mechanism 1 so operable as to actuate the canister 20 todeliver a dose of medicament. The chassis 40 retains most of themechanical components of the inhaler 100 in the correct position, and isheavily loaded. For example, most of the components of the triggermechanism are pivoted on the chassis 40, thus reducing problems causedby tolerance. The front opening in the housing 10 accommodates aregistration module (electronic module) 70 and an upper portion 32 of afacia 30, each having opposed side walls 34, respectively to fit flushwith the side walls 12 of the housing 10.

A mouthpiece 60 protrudes from the housing 10 and may be protected fromdamage and/or the entering of foreign bodies e.g. dust by locking oractuating means 2 pivotally mounted for movement on the chassis 40 asillustrated. In the embodiment shown, the actuating means is aprotective cover 2 and shall now be referred to as such. The cover 2 hasopposed side walls to fit flush with the side walls of the housing 10,and a rear curved wall to fit flush with the rear wall of the housing10. The rear walls of the respective housing and the cover together forma curved surface to facilitate comfortable receipt of the inhaler 100 inthe palm of the user's hand.

The canister 20 fits in the chassis 40 retained in the housing 10 andmay be slidably removed for replacement as illustrated in FIGS. 3 and 3a. The canister 20 is of a known type for holding a suspension orsolution of a medicament in a propellant under pressure. The canister 20comprises a generally cylindrical body 22 and a valve stem 24 which arecompressible together to deliver a dose of medicament from the valvestem 24. The canister 20 includes a metering chamber (not shown), whichcaptures a defined volume of medicament from the body 22 of the canister20, which volume of medicament is delivered as a metered dose from thevalve stem 24 on compression of the valve stem relative to the body 22.The valve stem 24 is biased outwardly to reset the canister 20 aftercompression for refilling the metering chamber. The valve stem 24 islocated in a nozzle block 62. The nozzle block 62 is formed as part of,and in open communication with, the mouthpiece 60 to direct a dose ofmedicament delivered from the valve stem 24 out of the inhaler 100through the mouthpiece 60.

An opening in the lower part 36 of the facia 30 is so sized and shapedas to receive the is mouthpiece 60, which is of a corresponding size andshape. According to one embodiment, there is provided a replaceablecanister module 37 comprising a canister 20 and a mouth piece 60 with anozzle block 62, wherein the canister body 22 is moveable in theactuation direction with respect to the nozzle block 62, and wherein thecanister module 37 is inserted in the actuator 10 in a directionessentially transverse to the actuation direction of the canister. Thecanister 20 is moveably connected to, and supported by, the facia 30 andthe mouth piece 60, by a collar 28 fitted around a necked portion of thecanister body 22. The collar 28 may be permanently fixed to the canister20, and comprises a connection member 29 that enables a linear motion ofthe canister 20 in the actuation direction with respect to the facia 30and mouthpiece 60. This allows actuation of the canister by compressionof the canister body towards the valve stem when the stem is fixedrelative to the inhaler in the nozzle block. In the disclosedembodiment, the collar 28 has a notched/‘keyed’inner surface engagingthe crimp joining the canister 20 and valve. In other embodiments, thecanister 20 may be interconnected with the facia 30 and the mouthpiece60 in another way. The canister 20 may be integral with the facia andthe mouthpiece 60 such that the facia and mouthpiece 60 are removed fromthe housing and inserted into the housing together with the canister 20as a canister module 37 as illustrated in FIGS. 3 and 3 a. When such acanister module 37 is inserted into the housing, the mouthpiece 60stands on a platform in the chassis and encloses the airflow. Themouthpiece 60 forms the end of an air passage through the housing, theinlet of the air passage being adjacent a trigger element. A clip 38retains the facia to the housing. The canister and collar have a smalldegree of movement along the axis of the canister to allow actuation ofthe canister.

The outer surface of the upper portion of the facia 30 carries anindication of the type of medicament in the canister 20 to which thefacia 30 is connected. The indication may be printed information, anembossed or indented pattern, for example, Braille, or the colour of thefacia.

The registration module 70 is responsive to firing of the actuator 100.According to one embodiment the registration module 70 is arranged todetect the presence of a canister module 37 in the actuator, andarranged to disregard firings of the actuator when no canister module 37is present. The detection of a canister module 37 may e.g. be performedby a microswitch (not shown) that is activated when a canister module 37is inserted into the actuator, e.g. by detection of a tab 261 extendingfrom the canister module for interaction with said microswich. Accordingto one embodiment, the canister module 37 comprises a non-use indicator260 that is preset in a non-use state and which is set in anirreversible in-use state at the first actuation of the canister module37. According to one embodiment, the non-use indicator 260 is a moveabletab, that initially in its non-use state is hidden from detection by theregistration module 70, and upon the first actuation (use) is moved toan exposed “in-use state” where the registration module 70 detects thepresence of the tab. When, the moveable tab has entered the in-use stateit is mechanically hindered from returning to its non-use state.Preferably, the moveable tab is hindered from being returned to itsnon-use mode by tamper proof means. The registration module 70 isarranged to detect the state of the of the non-use indicator 260, e.g.by a second microswitch, each time a canister module 37 is arranged inthe actuator, and in response to to a:

-   -   non-use state; initiate a new actuation counting cycle, and    -   in-use state; not count actuations.

As is evident to any person skilled in the art, the registration module70 may be an is electronic module or a mechanical counter module withthe same or essentially the same functionality.

The actuation mechanism 1 for actuating the canister 20 to deliver adose of medicament is illustrated in FIGS. 4, 4 a, 5, 5 a, 6 and 6 a.The actuation mechanism 1 operates to compress the canister body 22relative to the valve stem 24 held in the nozzle block 62 to deliver adose of medicament. The elements illustrated in FIGS. 4, 4 a, 5, 5 a, 6and 6 a are accommodated in the housing 10 and retained by the chassis40 but both the housing 10 and the chassis 40 are removed from FIGS. 4,4 a, 5, 5 a, 6 and 6 a for clarity.

The structure of the actuation mechanism 1 is as follows.

The actuation mechanism 1 comprises loading means or a loading element 6for loading the actuation mechanism 1 with an actuation force forcompression of the canister 20 to deliver a dose of medicament. Aresilient loading element 6, such as a coiled spring is provided for thestorage and release of the actuation force. The coiled spring 6 ismovable in one direction substantially along the cylindrical axis of thecanister 20 to store the actuation force, and in an opposite directionsubstantially along the cylindrical axis of the canister 20 to releasethe actuation force.

The coiled spring 6 is connected at its lower end to a yoke 4. The yoke4 has a canister-engagement portion. A cover element 8 may engage thecoiled spring 6 at its to upper end. The cover element 8 may facilitatethe spreading of the load on the coiled spring 6 into the housing 10 ofthe inhaler, and may also aid location of the coiled spring 6 within thehousing.

As illustrated in FIGS. 1-3, the actuation locking means, in the presentembodiment represented by the cover 2 is mounted for movement between afirst, or open, position relative to the housing 10, and a second, orclosed, position relative to the housing 10. In the embodiment shown,the cover 2 is pivotally mounted on the chassis 40 and has a cam 110 atthe pivot point 120. In this way, pivotal movement of the cover 2 to thefirst or open position allows the yoke 4 to move downwards, under theforce applied by the coiled spring 6. Conversely, pivotal movement ofthe cover 2 to the second or closed position applies an upward force tothe yoke 4 and forces it upwards, compressing the coiled spring 6. Theyoke is thus moveable in a direction substantially along the cylindricalaxis of the canister 20. As a result of the gearing inherent in the camloading mechanism, the total distance that the yoke 4 performs inresponse to pivotal movement of the cover 2 is greater than the distancewhich the canister body 22 and the valve stem 24 of the canister 20 needto be compressed in order to release a dose of medicament.

The actuation mechanism 1 further includes a trigger mechanism 3 forholding the loading element 6 against compression of the canister 20.The trigger mechanism 3 is constructed as follows.

A yoke lever 50 (lever 50) is pivoted about lever hinge pins 130 thatare arranged in mating hinge holes 132 in the chassis 40 and has a pairof lever arms 51 engaging the yoke 4 in a corresponding pair ofhorizontal yoke groves 140, whereby the lever 50 performs a pivotalmovement when the yoke 4 is moved upwards or downwards. At the distalend from the arms 51, the lever 50 has yoke lever lock end in the formof a planar portion 52 that is arranged to engage a lock rib 150 on alock member 53 (lever lock 53) when the lever lock 53 is in a lockedposition. The lever lock 53 is pivoted about lock hinge pins 160 thatare arranged in mating hinge holes in the chassis 40. In its lockedposition, as illustrated in FIGS. 5 and 5 a the lever lock 53 holds theloading means, via the lever 50, is against compression of the canister20.

The trigger mechanism further comprises latch means in the form of arelease member (drop link element) 55 movable between a latch positionarranged to store the actuation force to retain the canister 20 in therest or charging position, and a latch-release position arranged torelease the actuation force and allow compression of the canister 20.The drop link element 55 is pivotally connected at one end to the leverlock 53. The drop link 55 is provided at its other end with a latchingelement 56 adapted to engage a trigger element pivotally mounted on thechassis. The trigger element 57 is arranged for movement in response toinhalation by the user at the mouthpiece or manual depression by theuser of a firing button, to cause actuation of the canister 20 todeliver a dose of medicament to the mouthpiece. In the embodiment shown,the firing button is made integral with an inlet duct cover 64. However,it may not be made integral therewith. The firing button 48 enables theuser to deliver a dose of medicament as an emergency function if, forany reason, the usual actuation mechanism fails, or if the user cannotinhale significantly to activate the actuation mechanism to deliver adose of medicament for example, during a chronic asthma attack. In thepreferred embodiment, the trigger element 57 constitutes an inhalationresponsive trigger vane that is an element, which is moved in responseto and by a flow of air there over.

The latching element 56 contacts and rests upon the trigger vane 57 atits trigger pivot shaft 58 when the drop link 55 and trigger vane 57 areat their latch position.

Operation of the actuation mechanism will now be described withreference to FIGS. 4-6 which illustrate the various parts of theactuation mechanism in schematic form for ease of understanding.

FIG. 4 illustrates the neutral or “rest” position of the actuationmechanism in which is the cover 2 encloses the mouthpiece when theinhaler 100 is not in use. The yoke 4 is in its uppermost position sothat the coiled spring 6 is in a loaded state, thus storing an actuationforce. All mechanical components of the inhaler but the yoke 4 areunloaded and there is no compression of the canister 20. An air gapexists between the canister engagement portion of the yoke 4 and thebase of the canister 20. However, it can be envisaged that dampeningmeans, such as a foam or rubber element, may be placed between the yoke4 and the canister 20. The lever 50 and the lever lock 53 are both intheir locked positions. The drop link 55 is in its latched positionwhereby the latching element 56 rests upon the pivot shaft 58 of thetrigger element 57, thereby holding the lever lock 53 in its lockedposition.

When the inhaler 100 is to be used, the cover 2 is opened to access themouthpiece, as shown in FIG. 5. Upon pivotal movement to open the cover2, the yoke 4 is moved downwardly to engage the base of the canister 20.In this state, the coiled spring 6 biases compression of the canister 20via the yoke 4, and the yoke 4 compresses the canister 20 relative tothe valve stem a distance of about 0-2 mm. However, further compressionof the canister 20 to deliver a dose of medicament is prevented by theload applied to the trigger mechanism. The lever lock 53 holds theloading means, via the lever 50, in its locked position, againstcompression of the canister 20. The lever 50 and the lever lock 53remain in their locked position, the planar portion of the lever 50being forced against the lock rib 150 on the lever lock 53. In this“armed” or charging state, inhaler 100 is loaded ready for the deliveryof a dose of medicament.

Inhalation by the user at the mouthpiece causes air to flow through theair flow path defined inside the housing from the inlet opening to themouthpiece. Due to the pressure drop created by the flow inside thehousing 10 (or use of the firing button as previously is described), thetrigger element 57 is caused to pivot in a flow direction to itslatch-release position illustrated in FIG. 6. Pivotal movement of thetrigger element 57 to its latch release position causes the drop link 55to pivot in an upwards direction to its release position. Pivotalmovement of the drop link 55 in turn causes the latching element 56 tobe lifted over and to disengage from the pivot shaft 58 of the triggerelement 57. The pivot shaft 58 of the trigger element 57 may besubstantially circular in cross section, however any shape may beenvisaged, such as a sector of a circle, provided that upon rotation ofthe pivot shaft 58, there is sufficient surface provided to allow thelatching element 56 to be lifted over and to disengage from the pivotshaft 58. The pivotal movement of the drop link 55 thus causes the leverlock 53 to pivot in the release direction from its locked or armedposition to its release position, to allow compression of the canisterby disengagement of the planar surface 52 from the rib. The lever 50 inits unlocked state allows compression of the canister 20 to deliver adose of medicament under the biasing of the coiled spring 6. In thisstate the inhaler may be described as being in its “fired”, “triggered”position or “medicament discharging position”.

The lever lock 53 has a re-set spring 210 which forces it to pivot backand to return to its latching position. The droplink 55 uses anotherspring leg 250 of the same reset spring 210, however in this case thereset spring allows it to pivot back to return to a reset position readyto take up its latching position. In its reset position, the latchingelement 56 of the droplink element 55 abuts the pivot shaft 58 of thetrigger element 57. Each of the re-set springs is made from a plasticsmaterial or metal. The provision of re-set springs ensures that both thetrigger element 57 and the droplink 55 are ready to take up or return totheir latch position, respectively, without reliance on gravitationalforce.

Closure of the cover 2 causes the yoke 4 to move upward, which has threeeffects. Firstly, it allows the canister 20 to reset itself. Secondly,it causes the lever 50 and the lever lock 53 to return to their lockedposition in the neutral position of the actuation mechanism illustratedin FIG. 4, and the droplink 56 to return its latch position. Thirdly, itstores the actuation force in the coiled spring 6, via the loading ofthe yoke 4, ready for when the inhaler 100 is to be used.

FIGS. 8 a to 8 f show a schematic embodiment of one embodiment of abreath actuated inhaler (BAI) actuator adapted to show the function ofthe actuation mechanism in detail. The BAI actuator 100 comprises aloading element 6, a breath actuated trigger mechanism 3 and actuationlocking means 2.

The loading element 6 provides the force necessary for actuation of themetering valve of the canister, and needs therefore to be capable ofbeing loaded with an actuation force of suitable magnitude. Theactuation force required for actuation of the metering valve depends onthe type of metering valve and, to some extent, on the type oftriggering mechanism. In one embodiment the loading element 6 may beintegrated in the metering valve, thus excluding the need for a separateloading element. In FIGS. 8 a to 8 f the loading element 6 isillustrated as a coiled spring, but it may be of any suitable type thatis capable of being loaded with the required actuation force.

The breath actuated (BA) trigger mechanism 3 is arranged to counteractthe actuation force of the loading element 6 and to fire the actuator100 by releasing the actuation force of the loading element 6 inresponse to an inhalation breath. One example of a BA trigger mechanismis disclosed in detail below, but there are many other types of BAtrigger mechanisms that can be used in the present BAI actuator. Oneexample is a mechanism of catch member type, wherein a trigger elementis arranged to release a catch member in response to a breath flow.Another example is a mechanism of bistable pivot joint type, wherein atrigger element is pivotal between an armed position wherein itcounteracts the actuation force via a pivot joint restricted to a jointangle close to, but less than, 180° and a fired position, wherein thetrigger element is arranged to pivot the joint angle beyond 180° inresponse to a breath flow, thereby releasing the actuation force. Butother mechanisms or combinations thereof may also be used.

As mentioned above, many components in the trigger mechanism are smallsized and often made of plastic material and therefore susceptible tomaterial creep upon prolonged loading. Therefore, the actuator isprovided with actuation locking means 2 moveable between a lockedposition (FIG. 8 f) wherein it relieves the actuation force from thetrigger mechanism setting the trigger mechanism 3 in a neutral orunloaded position, and an armed position (FIG. 8 a) wherein the triggermechanism 3 is set in an armed position. In the disclosed embodiment,the actuation locking means 2 is further arranged to function asactuating means that are arranged to load the loading element 6 withactuation force upon movement from its armed position to its lockedposition (FIGS. 8 d and 8 e), after the actuator is fired. According toone embodiment, not shown in figure, the actuation locking means 2 isprovided separately from the actuating means.

In the disclosed embodiment the actuation locking means 2 is formed as apivotal lever with a helical cam member 110 arranged about a pivotalpoint 120. Upon movement of the locking means 2 after the actuator isfired, from its armed position (FIG. 8 c) to its locked position (FIG. 8f), the helical cam member 110 acts on a loading yoke 4, initially toload the loading element 6 with actuation force (FIGS. 8 d and 8 e) andto arm the trigger mechanism 3 (FIG. 8 e), and subsequently to overloadthe loading element to relieve the actuation force from the triggermechanism 3 setting it in a neutral or unloaded position (FIG. 8 f).Upon subsequent movement of the locking means 2 from its locked positionto its armed position, the helical cam member 110 initially acts on theloading yoke 4 to unload the overloading force on the loading element 6to arm the trigger mechanism, where after it is moved to its armedposition, wherein the helical cam is in a position that allows firing ofthe actuator (FIG. 8 a).

According to one embodiment, the helical cam member 110 is formed sothat the actuation locking means 2 is retained in the locked position bythe actuation force of the loading element 6. In the disclosedembodiment, the helical cam member is formed so that the active section170 that is in contact with the yoke 4 is either flat or inclined sothat the actuation force gives rise to a stable state or that theactuation locking means 2 is urged in the locked direction. In thedisclosed embodiment, the actuation locking means 2 is formed as aprotective cover 2 arranged to limit the access to the mouth piece 60 inits locked position and to allow access to the same in its armedposition.

In the disclosed embodiment, the BAI actuator is arranged for actuationof a compression firing canister of the type disclosed more in detailabove. However, according to other embodiments, the BAI actuator may bearranged for actuation of canisters with other types of metering valves,such as valves that fire upon withdrawal of a control stem, rotary typevalves and the like. Moreover, according to one embodiment, the meteringvalve may be of a type that is biased in the firing direction, and insuch case, the biasing force of the metering valve, may be used in lieuof or in combination with the loading element 6.

In the disclosed embodiment, the loading element 6 is arranged to act onthe canister body 22 of the canister 20, and the actuation involvesdepressing the canister body 22 of the canister with respect to a staticnozzle block 62. In another embodiment, not disclosed in the figures,the loading element 6 is arranged to act on a moveable nozzle block,wherein actuation involves translation of the nozzle block with respectto the canister body 22 of the canister 20 to depress the valve stem 24.

According to one embodiment the loading element 6 is arranged to act onthe non valve end of the canister body 22 arranged in the BAI actuator100, via the yoke 4. In the disclosed embodiment, the loading element 6is a coiled spring arranged in alignment with the actuation direction ofthe canister 20. The yoke 4 comprises two cam follower legs 180 for caminteraction with, and transmission of, loading translation from thehelical cam 110 to the loading element 6. According to one embodiment,as is exemplified by the embodiment of FIGS. 1 to 7, the cam followerlegs 180 are arranged to extend along diametrically opposite sides ofthe canister 20, whereby the force transmitted from the actuationlocking means 2 via the helical cam 110 to the loading element 6 isaligned with actuation direction of the canister 20. In the embodimentof FIGS. 8 a to 8 f, the yoke 4 comprises two cam follower legs 180 thatare parallel, but not diametrically arranged with respect to thecanister 20, mainly in order to make the figure clearer, but also inorder to show that the cam follower legs 180 need not to be in perfectalignment with the actuation direction of the canister.

According to one embodiment, the trigger mechanism 3, the yoke 4 and theactuation locking means 2, are supported by a chassis 40 arranged in anexternal housing 10. As mentioned above, the chassis gives rigidity tothe actuator, and by supporting all moveable parts by the chassis 40problems relating to tolerances between different parts are reduced. InFIGS. 8 a to 8 f the chassis 40 is reduced to a strict illustrativedesign, to make the function of the actuation mechanism 1 clearer,whereas the embodiment shown in FIGS. 1 to 7 comprises a chassis 40 thatallows a more compact and load efficient design. In the disclosedembodiments, the cam follower legs 180 are arranged for and limited tolinear movement in mating yoke grooves 140 formed in the chassis 40.

FIGS. 8 a to 8 f show one embodiment of a trigger mechanism comprising:

-   -   a yoke lever 50 arranged to transform the movement of the yoke 4        to a pivotal movement of a lock end 52 thereof,    -   a lock member 53 pivotally moveable between an armed position        (FIG. 8 a) wherein it is arranged to prevent further pivotal        movement of the yoke lever lock end 52 in the actuation        direction, and an open position wherein the yoke lever 50 is        free to move beyond the armed position in the actuation        direction, in the armed position the lock member 53 is biased        towards the open position by the yoke lever 52 which in turn is        biased in the actuation direction by the loading element 6 via        the yoke 4,    -   a trigger element 57 arranged for movement in response to an        inhalation breath, and    -   a release member 55 arranged between the lock member 53 and the        trigger element 57 to hold the lock member 53 in the armed        position, and to release the lock member 53 in response to        movement of the trigger element 57.

The yoke lever 50 is pivotally supported by the chassis 40 by leverhinge pins 130 or the like, and comprises lever arms 51 that arearranged to engage corresponding yoke grooves 140 formed in the yoke 4.The yoke lever 50 is formed to create a lever effect gearing down theforce applied on the components in the triggering mechanism from theloading element 6. The gearing is achieved in that the longitudinaldistance between the hinge pivot point 130 and the lever arms 51 isshorter than the distance between the hinge pivot point 130 and the yokelever lock end 52. In the disclosed embodiment, the yoke lever 50 isarranged so that the lock end 52 performs an upward movement when theyoke 4 moves downwards, but in an alternative embodiment the yoke lever50 may be formed to reverse the direction of movement by arranging thelever arms 51 in between the hinge pivot point 130 and the lever lockend 52. In the later case, the other parts of the trigger mechanism mustbe adapted to the reversed direction of movement.

In the disclosed embodiment, the lock member 53 is pivotally supportedby the chassis by lock hinge pins 160. The lock member 53 comprises alock rib 150 arranged to act as a catch member for the lock end 52 ofthe yoke lever 50 to arm the triggering mechanism. The pivot point 160of the lock member 53, and the interaction between the lock rib and thelock end 52 of the yoke lever 50 are arranged so that the lock member 53is biased towards the open position by the yoke lever 50. By designingthis interaction properly a suitable gear down effect is achieved,reducing the force applied on the components of the trigger mechanismeven further. A spring element 210 biases the lock member 53 in theclosing direction, towards the yoke lever 50, in order to reset thetrigger mechanism during loading of the actuation mechanism, as is shownin FIG. 8 d. The yoke lever 50 comprises a lock member guide surface 200at the lock end thereof. As is shown in FIG. 8 c, the lock member guidesurface 200 interacts with the lock rib 150 to hold the lock member inthe open position when the actuator is unloaded.

The trigger element 57 is arranged at one end of an air flow duct 190extending from the mouth piece 60 at the other end. The air flow duct190 may be formed by the actuator housing 10, the chassis 40, or acombination thereof, and optionally with additional components.According to one embodiment, the trigger element is a pivotal vane witha trigger pivot shaft 58 that is pivotally supported by the chassis 40at a trigger pivotal point and arranged to pivot about a the pivot axisin response to an air flow in the flow duct, e.g. an inhalation breath.The release member 55 is, at one end, pivotally connected to the lockmember at a release pivot point 240, and at the other end it is arrangedto interact with the trigger pivot shaft 58 to hold the lock member 53in the armed position, and to release the lock member 53 in response topivotal movement of the trigger pivot shaft 58. According to oneembodiment, the release member 55 is a drop link element.

FIGS. 10 a, 10 b, 11 a and 11 b show two embodiments of trigger vane andrelease member combinations. The trigger pivot shaft 58 comprises anessentially semi cylindrical shaped release surface 220, and stop means230 that ensure that the release member 55 enters the correct armedposition upon arming the triggering mechanism 3. As mentioned above, therelease member 55 is biased in the direction of the trigger pivot shaft58 by the lock member 53, which in turn is biased in the openingdirection by the loading element 6 via the yoke lever 50. In the armedposition (FIG. 8 a), the release member 55 is arranged to apply thebiasing force in a direction that is essentially radial to the triggerpivot axis 58. When the trigger vane 57 is pivoted by an air flow in theair flow duct 190, the interaction end of the release member 55 rotatestogether with the trigger pivot shaft 58, and the direction of thebiasing force is shifted (lifted) from the trigger pivot axis 58 (FIG. 8b), and upon sufficient rotation the shifted biasing force makes therelease member 55 detach from its armed state whereby the actuator isfired (FIG. 8 c). In FIGS. 10 a and 10 b, stop means 230 of the triggerpivot shaft 58 are provided on both sides of a semi cylindrical releasesurface 220, and the corresponding release member comprises two stopprotrusions 260 that are arranged to abut the stop means 230 of thetrigger element. In FIGS. 11 a and 11 b the support means is formed by astop ridge 230 at the lower end of the release surface 220. Moreover,the stop means 230, ensures that the release member 55 rotates togetherwith the trigger pivot shaft 58. In order for the release member 55 toreturn to the armed position resting upon the trigger pivot shaft 58upon loading of the actuator mechanism 1, a reset spring member 250 isarranged to bias the release member 55 in the downwards direction (FIG.8 e).

FIGS. 8 a to 8 f schematically shows the BAI actuator in differentstates of operation, wherein:

-   -   FIG. 8 a illustrates the armed state, when the actuator is ready        to be fired by an inhalation breath (FIGS. 8 b and 8 c) or by        use of the firing button 48. The protective cover 2 which        functions as loading means and actuation locking means is in its        open or armed position whereby the actuation mechanism is able        to be fired. As is discussed in detail above, the loading        element 6 is loaded with an actuation force that exceeds the        reset bias force in the metering valve of the canister 20, and        the triggering mechanism 3 counteracts the actuation force via        the yoke 4.    -   FIG. 8 b illustrates an initial phase of a firing of the        actuator by an inhalation breath, wherein the trigger vane 57 is        pivoted an amount, but the release member 55 is still in locking        contact with the trigger pivot shaft 58 and thus prevents firing        of the actuator.    -   FIG. 8 c illustrates the fired state, wherein the trigger vane        57 is further pivoted and the release member 55 has been        detached from the pivot shaft 58 and the lock member 53 is        pivoted to release the yoke lever 50 whereby the actuation force        is released and the canister 20 is depressed to fire a dose of        medicament into the inhalation air flow through the mouth piece        60.    -   FIG. 8 d illustrates the process of loading the loading element        6 and arming of the trigger mechanism 3. The protective cover 2        is pivoted in the closing direction, whereby the helical cam 110        forces the yoke 4 in the loading direction and the yoke lever 50        is pivoted in the armed direction. The lock rib 150 of the lock        member 53 follows the guide surface 200 of the yoke lever 50,        biased by the spring element 210.    -   FIG. 8 e illustrates a state wherein the protective cover 2 is        further pivoted in the closing direction, whereby loading        element is essentially fully loaded, and the triggering        mechanism has entered its armed state.    -   FIG. 8 f illustrates the locked state of the actuation        mechanism, with the protective cover 2 closed and wherein the        helical cam 110 is arranged to “over load” the loading element 6        via the yoke 4, whereby the trigger mechanism is unloaded,        referred to as the neutral position.    -   In order to fire the actuator 100, the cover is pivoted back to        the initial state as is illustrated in FIG. 8 a.

1.-18. (canceled)
 19. An inhaler, comprising: a chassis configured toreceive a canister containing a medicament; a trigger moveably coupledto the chassis and configured to move to initiate firing of thecanister; a lock system moveably coupled to the chassis, wherein thelock system comprises: a droplink moveable relative to the trigger; alever lock hingedly coupled to the droplink; and a lock springconfigured to bias the lock system relative to the chassis; a yoke levermoveably coupled to the chassis, wherein the yoke lever is moveablerelative to the lock system; and a loading element configured to biasthe canister relative to the chassis, wherein the yoke lever is moveablycoupled to the loading element and the loading element is configured tomove to fire the canister.
 20. The inhaler of claim 19, wherein thetrigger is rotationally coupled to the chassis.
 21. The inhaler of claim19, wherein the lock system is rotationally coupled to the chassis. 22.The inhaler of claim 19, wherein the lock spring is configured to biasthe droplink relative to the lever lock.
 23. The inhaler of claim 22,wherein the lock spring is configured to bias the lever lock relative tothe chassis.
 24. The inhaler of claim 19, wherein the droplink isreleasably coupled to the trigger.
 25. The inhaler of claim 19, whereinthe lever lock is releasably coupled to the yoke lever.
 26. The inhalerof claim 19, further including a yoke moveably coupled to the yoke leverand configured to move to bias the loading element.
 27. The inhaler ofclaim 19, wherein the lock system includes a rib configured toreleasably couple to an end of the yoke lever.
 28. The inhaler of claim19, wherein the lock system includes a flat surface configured toreleasably couple to a corresponding flat surface of the yoke lever. 29.An inhaler, comprising: a chassis configured to receive a canistercontaining a pressurized medicament; a trigger rotatably coupled to thechassis and configured to rotate in response to an inhalation; a locksystem comprising: a droplink slideably coupled to the trigger; a leverlock rotatably coupled to the droplink and rotatably coupled to thechassis; and a lock spring configured to bias the droplink relative tothe lever lock; a yoke lever rotatably coupled to the chassis, whereinthe yoke lever is slideably coupled to the lock system; and a loadingelement configured to bias the canister relative to the chassis, whereinthe yoke lever is configured to move to release the loading element tofire the canister.
 30. The inhaler of claim 29, wherein the lever lockis pivotally connected to the droplink.
 31. The inhaler of claim 29,wherein the lock spring is configured to bias the lever lock relative tothe chassis.
 32. The inhaler of claim 29, wherein the droplink isreleasably coupled to the trigger.
 33. The inhaler of claim 29, whereinthe lever lock is releasably coupled to the yoke lever.
 34. The inhalerof claim 29, wherein the lever lock includes a rib configured toreleasably couple to an end of the yoke lever.
 35. The inhaler of claim34, wherein the rib has a flat surface configured to transmit acompressive force to a corresponding flat surface of the end of the yokelever.
 36. The inhaler of claim 35, wherein the flat surface of the ribis slideable relative to the corresponding flat surface of the end ofthe yoke lever.
 37. A locking system for use with an inhaler having acanister containing a pressurized medicament, comprising: a droplinkreleasably coupled to a trigger configured to move in response to aninhalation; a lever lock pivotally connected to the droplink andpivotally connected to the inhaler; and a lock spring configured to biasthe droplink relative to the lever lock, wherein the lever lock isconfigured to move relative to the inhaler to release a biased loadingelement to fire the canister.
 38. The locking system of claim 37,wherein the lever lock includes a flat surface configured to sliderelative to a corresponding flat surface of a yoke lever to releasablycouple the lever lock from the yoke lever to fire the canister.